Vitamin K
Measures vitamin K levels to assess blood clotting function and evaluate potential deficiency that may affect bone health and coagulation.
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What this test measures
Vitamin K blood test measures vitamin K levels in the blood to screen for vitamin K deficiency and assess blood clotting function, bone metabolism, and potential hemorrhagic disorders. The test typically measures vitamin K1 (phylloquinone), with reference serum levels for adults aged 18 years and above being 0.10-2.20 ng/mL.
Vitamin K comprises a group of fat-soluble compounds involved in essential processes such as blood clotting, bone metabolism, and cardiovascular health. Vitamin K plays an important role in coagulation, helping produce the proteins that work during the blood clotting process. It serves as a cofactor for γ-glutamyl carboxylase, catalyzing post-translational γ-carboxylation of certain glutamic acid residues on coagulation proteins, including factors II (thrombin), VII, IX, and X, as well as anticoagulant proteins C, S, and Z.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing unexplained bleeding, excessive bruising, or prolonged bleeding from minor cuts may benefit from vitamin K testing to evaluate potential deficiency.
- Those with malabsorption conditions such as celiac disease, Crohn's disease, cystic fibrosis, or liver disease should consider testing as these conditions can impair vitamin K absorption.
- Individuals taking long-term antibiotic therapy may need testing since certain antibiotics can disrupt gut bacteria that produce vitamin K or interfere with its metabolism.
- People with poor dietary intake of vitamin K-rich foods (green leafy vegetables, certain oils) or those following very restrictive diets may benefit from assessment of their vitamin K status.
- Adults taking anticoagulant medications like warfarin should discuss vitamin K testing with their healthcare provider to help monitor their nutritional status and medication effectiveness.
What to expect
Preparation
Fast for 12 hours before the blood draw and avoid alcohol for 24 hours prior. Avoid vitamin K supplements and vitamin K-rich foods for 24 hours before testing. Continue taking prescribed medications unless otherwise directed by your healthcare provider.
Sample Type
A healthcare professional will draw a blood sample from a vein in your arm using a standard needle and collection tube. The sample must be protected from light during collection and processing.
Collection
The blood draw typically takes just a few minutes at the lab location. No doctor visit required --- simply present your lab order and valid ID at the collection site.
Turnaround
Results are typically available within 7-10 business days and will be securely delivered through your online patient portal.
Understanding your results
For adults aged 18 years and above, normal vitamin K1 levels typically range from 0.10-2.20 ng/mL. Interpreting vitamin K blood test results requires clinical context, as reference ranges may vary between laboratories and testing methods.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 0.10-2.20 ng/mL | Normal range for vitamin K1 (phylloquinone) levels in serum |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Vitamin K deficiency can contribute to significant bleeding, poor bone development, osteoporosis, and increased cardiovascular disease risk. The main symptom of vitamin K deficiency is excessive bleeding, which is the telltale sign of deficiency. Impaired blood clotting has been associated with vitamin K levels below 0.5 ng/mL. Low levels may be caused by inadequate dietary intake, malabsorption disorders, certain medications, or conditions affecting liver function.
What does a “High” result mean?
Elevated vitamin K levels may be associated with recent consumption of supplements or foods high in vitamin K, which can elevate plasma concentrations. Higher than normal levels are generally not considered harmful, as vitamin K is metabolized quickly and excreted in urine or stool and typically doesn't reach toxic levels even with high intakes. Elevated levels might indicate recent dietary intake of vitamin K-rich foods or supplementation.
Privacy & confidentiality
Your vitamin K test results are completely confidential and protected under HIPAA regulations. Results are not shared with your personal physician unless you choose to do so, are not added to your medical record, and do not appear on insurance explanations of benefits since no doctor visit is required.
Frequently asked questions
Related tests
Coagulation Panel
$49Evaluates overall blood clotting function and complements vitamin K assessment
View TestVitamin D
$59Works synergistically with vitamin K for optimal bone health and calcium metabolism
View TestVitamin B12
$49Part of comprehensive nutritional assessment for individuals with suspected deficiencies
View TestLiver Panel
$39Assesses liver function, which is important for vitamin K metabolism and storage
View TestCPT Code: 84597
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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Not sure if this is the right test? Contact our care team for guidance.